Air Pollution Board Votes to Reclassify Rubbertown Chemical

Louisville’s Air Pollution Control Board has voted to re-categorize a chemical used in some of the city’s manufacturing processes. Recent studies have suggested the chemical isn’t as carcinogenic as originally thought.

When the Air Pollution Control District created the city’s Strategic Toxic Air Reduction program in 2005, ethyl acrylate was added to the list as a carcinogenic Category 1 Toxic Air Contaminant. That was based on a study from the 1980s that injected the chemical orally into rats and was found to cause cancer.

But now new studies have suggested that ethyl acrylate isn’t a carcinogen—or, at least, it’s only a carcinogen if large volumes are frequently injected directly into the stomach. The new data says that touching or breathing in the chemical won’t cause cancer.

APCD spokesman Tom Nord says the district needs to classify chemicals based on the best science, and the STAR program is meant to evolve along with the science.

“That’s where we are. We have to respond to what we know,” he said. “You don’t write a regulation and just leave it be forever. You have to be willing to add things and take things away. And that’s essentially what’s going on with the ethyl acrylate.”

Nord says technically the decision means companies can use more ethyl acrylate in their processes. But he doesn’t expect it to have any practical implications, because companies use the chemical in processes that rely on other carcinogenic substances.

“You’re not going to see like a big huge wave of ethyl acrylate production here or use,” he said. “This is more about getting our regulations in sync with the rest of the scientific community.”

The board voted five to one in favor of re-classifying ethyl acrylate as a category 4 non-carcinogen. Board member and physician Nadir al-Shami voted against the amendment, suggesting it would be better to err on the side of caution.